﻿using System.ComponentModel;

namespace System.Globalization
{
    /// <summary>
    /// 对数组的扩展方法
    /// </summary>
    [EditorBrowsable(EditorBrowsableState.Never), Browsable(false)]
    public static class ChineseLunisolarCalendarExtension
    {
        /// <summary>
        /// 十天干
        /// </summary>
        private static string[] _tiangan = { "甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸" };

        /// <summary>
        /// 十二地支
        /// </summary>
        private static string[] _dizhi = { "子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥" };

        /// <summary>
        /// 十二生肖
        /// </summary>
        private static string[] _shengxiao = { "鼠", "牛", "虎", "免", "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪" };

        /// <summary>
        /// 返回农历天干地支年
        /// </summary>
        /// <param name="year">农历年</param>
        /// <returns></returns>
        public static string GetLunisolarYear(int year)
        {
            if (year > 3)
            {
                int tgIndex = (year - 4) % 10;
                int dzIndex = (year - 4) % 12;

                return string.Concat(_tiangan[tgIndex], _dizhi[dzIndex]/*, "[", shengxiao[dzIndex], "]"*/);
            }

            throw new ArgumentOutOfRangeException("无效的年份!");
        }

        /// <summary>
        /// 获得指定公历日期中对应的农历天干地支年
        /// </summary>
        /// <param name="calendar"></param>
        /// <param name="date"></param>
        /// <returns></returns>
        public static string GetLunisolarYear(this ChineseLunisolarCalendar calendar, DateTime date)
        {
            return GetLunisolarYear(calendar.GetYear(date));
        }

        /// <summary>
        /// 农历月
        /// </summary>
        private static string[] months = { "正", "二", "三", "四", "五", "六", "七", "八", "九", "十", "十一", "十二(腊)" };

        /// <summary>
        /// 返回农历月
        /// </summary>
        /// <param name="month">月份</param>
        /// <returns></returns>
        public static string GetLunisolarMonth(int month)
        {
            if (month < 13 && month > 0)
            {
                return months[month - 1];
            }

            throw new ArgumentOutOfRangeException("无效的月份!");
        }

        /// <summary>
        /// 返回指定公历日期对应的农历月
        /// </summary>
        /// <param name="calendar"></param>
        /// <param name="date"></param>
        /// <returns></returns>
        public static string GetLunisolarMonth(this ChineseLunisolarCalendar calendar, DateTime date)
        {
            var month = calendar.GetMonth(date);
            var leapMonth = calendar.GetLeapMonth(calendar.GetYear(date));
            var isleep = leapMonth > 0 && leapMonth == month;

            if (leapMonth > 0)
            {
                if (leapMonth <= month)
                    month--;
            }

            return string.Concat(isleep ? "闰" : string.Empty, GetLunisolarMonth(month), "月");
        }

        /// <summary>
        /// 日期前缀
        /// </summary>
        private static string[] days1 = { "初", "十", "廿", "三" };

        /// <summary>
        /// 日
        /// </summary>
        private static string[] days = { "一", "二", "三", "四", "五", "六", "七", "八", "九", "十" };

        /// <summary>
        /// 返回农历日
        /// </summary>
        /// <param name="day"></param>
        /// <returns></returns>
        public static string GetLunisolarDay(int day)
        {
            if (day > 0 && day < 32)
            {
                if (day != 20 && day != 30)
                {
                    return string.Concat(days1[(day - 1) / 10], days[(day - 1) % 10]);
                }
                else
                {
                    return string.Concat(days[(day - 1) / 10], days1[1]);
                }
            }

            throw new ArgumentOutOfRangeException("无效的日!");
        }

        /// <summary>
        /// 返回农历日
        /// </summary>
        /// <param name="day"></param>
        /// <returns></returns>
        public static string GetLunisolarDay(this ChineseLunisolarCalendar calendar, DateTime datetime)
        {
            return GetLunisolarDay(calendar.GetDayOfMonth(datetime));
        }

        /// <summary>
        /// 返回生肖
        /// </summary>
        /// <param name="datetime">公历日期</param>
        /// <returns></returns>
        public static string GetShengXiao(this ChineseLunisolarCalendar calendar, DateTime datetime)
        {
            return _shengxiao[calendar.GetTerrestrialBranch(calendar.GetSexagenaryYear(datetime)) - 1];
        }

        /// <summary>
        /// 获得指定公历的农历表述方式
        /// </summary>
        /// <param name="calendar"></param>
        /// <param name="date"></param>
        /// <returns></returns>
        public static string GetLunisolarDateString(this ChineseLunisolarCalendar calendar, DateTime date)
        {
            return calendar.GetLunisolarYear(date) + "年" + calendar.GetLunisolarMonth(date) + calendar.GetLunisolarDay(date);
        }
    }
}